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Environmentally Friendly Moorings Overview

Environmentally friendly moorings, or eco moorings, are mooring systems designed to have less impact on the sea bed than conventional swing moorings. They aim to minimise interaction with the seabed to prevent abrasion and therefore the potential to damage sensitive habitats.

What is the benefit of an EFM?

Traditional mooringFigure 1: Traditional mooring (RYA)

Zostera marina mooring scour, SalcombeFigure 2: Zostera marina mooring scour, Salcombe (Keith Hiscock1)

Traditional moorings are often similar in design to that shown in Figure 1. The mooring can be broken into three basic constituent parts, although this does vary in design between moorings:

  • The anchor - the method of weighting the mooring to the seabed (often a block);
  • The rode - the connection between the anchor and float (often chain with a heavier component that lies along the seabed and a lighter component that rises up through the water column); and
  • The float - the part that ensures the mooring is able to be picked up at the water surface (often a buoy). 

Any part of the mooring that interacts with the seabed has the potential to damage the substrate. The anchor, while covering a minimal area of substrate, is a static object and so potential impacts are limited to the area directly beneath it. The heavier chain part of the rode is designed to hold the vessel attached to the mooring in situ independent of the state of the tide. As the tide rises and falls, differing amounts of chain will lie across the seabed, and will be pulled around in a circle as the tide changes. This can cause abrasion of any substrate the chain comes into contact with, as in the example in Figure 2. Seagrass (Zostera marina) is particularly susceptible to damage in this way. Further impacts can be seen in Figure 3. 

Mooring damageFigure 3: Mooring impact at Salcombe (Left; Nigel Mortimer), and in the Scilly Isles (right)

Environmentally Friendly Moorings (EFM) are designed to reduce the interaction of the mooring with the seabed. Various EFM designs exist, with changes often made to the rode (such as though using an elastic component that does not lie along the seabed) or the anchor (through using for example a helical component rather than a block). Further information on types of EFM and some manufacturers can be found on the 'types of environmentally friendly moorings' page. 

Are EFMs suitable for use in the UK?

EFMs have become well established in both Australia and the USA, but have been slower to become established for use in the UK, partly due to the large tidal ranges seen in many areas. However, in recent years, various projects have taken place to trial EFMs, or have been installed by individuals for private use. Most of the projects have been very successful, with some EFMs in place since 2004. 

Further information on specific UK EFM installations can be found on the 'EFM projects and trials' page. 

Why these pages?

In October 2017, a workshop on EFMs was held by the National Trust with Natural England and the Marine Management Organisation, to bring together all parties with an interest in EFMs to discuss their status, current projects, and future. Discussions involved users, regulators and advisors. As a result of this workshop, which identified the need to improve the sharing of information, a decision was made to create a set of pages to bring together UK experience of EFMs, and the RYA offered to host these pages. The information presented here is a collaboration from partners including the National Trust, Natural England, Natural Resources Wales, the Marine Management Organisation, the Royal Yachting Association and The Crown Estate. 

We welcome further input on EFM experiences and trials, and any documentation, reports or papers. If you would like to provide any information, please fill in the form available below.  

1) Area of abrasion in a seagrass bed- (Salcombe, south-west England - Keith Hiscock) in Griffiths, C.A., Langmead, O.A., Readman, J.A.J., Tillin, H.M. 2017 Anchoring and Mooring Impacts in English and Welsh Marine Protected Areas: Reviewing sensitivity, activity, risk and management. A report to Defra Impacts Evidence Group.

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